Its hit or miss I guess. I ran my car for a few days VTA and didnt like it all that much. Best setup is recirc obviously. Wish somebody would come out with a blow through maf. Meaning you can have your bov before the maf and wouldnt make a difference since its reading exactly what air is going into the engine close to the throttle body.
Bov Help
- Thread starter amilliems6
- Start date
- :
- 2007 Mazdaspeed 6 Sport
Everyone on the internet should know that hitting the keys harder does not make you more correct. You guys need to cool it. Everyone is going to have their own opinion.
This community is meant for constructive criticism and mature, healthy debate. If you want to be a part of it you need to be civil or just ignore one another.
We're all fans of the same platform so we all have at least that in common. Work together to learn from each other and find solutions to one another's problems. Not everyone is going to agree every time. There will always be people who do their own thing. There's no use bitching at one another.
Help the community and its members grow. Don't push them away by subjecting them to this bulls***.
This community is meant for constructive criticism and mature, healthy debate. If you want to be a part of it you need to be civil or just ignore one another.
We're all fans of the same platform so we all have at least that in common. Work together to learn from each other and find solutions to one another's problems. Not everyone is going to agree every time. There will always be people who do their own thing. There's no use bitching at one another.
Help the community and its members grow. Don't push them away by subjecting them to this bulls***.
patty AT forge
Member
You can't use the FMDVMAZ3 as a vent to atmosphere valve. It is a single piston unit and will be open pretty much whenever the manifold is in vacuum and this will cause a huge leak. We make a separate vent to atmosphere valve the FMDVMAZ301 that has a secondary piston that stays closed to prevent leaking. But you are correct about plugging the recir tube, we include a billet plug with the VTA valve.
- :
- 2011 Mustang GT
Guys, this is getting out of hand. VTA or recirc, it doesn't matter. This thread is closed until it can be cleaned up.
What is this pen test you speak of.... would like to verify mine leaks.
illeztimportz
Member
- :
- MazdaSpeed6
hey folks. sorry noob here. but im still so confused about this whole bov/bpv thing. would it be a problem to just purchase an aftermarket bov/bpv (hks, turbosmart, forge ms, etc) and install onto a stock motor? i hear that if you do this the car would be harder to drive? ie: stalling?
You may have issues with a "blow off valve", other wise known as VTA or vent to atmosphere. The cause of the problem is the air that is "blown off" has been counted by the mass air sensor, and fueling will expect it to be used. This will cause the computer to have issues properly controlling the fueling. If you connect the BOV input back to the turbo inlet, then you have "made" a BPV or "bypass valve", otherwise known as a recirculation valve. This ensures all the air that enters the system is counted and used in the engine. hope that helps clear it up.
Jon
Jon
With a modern fuel injected engine, the ECU (engine computer) calculates the amount of air entering the engine through the MAF/MAS/AFM/etc... (Mass Airflow Sensor) as the main variable for metering fuel.
More air entering = more fuel needed.
In the MS6, air passes through the filter, then the MAF, then to the turbo, then to the intake manifold. The OEM BPV (as in any turbocharged car) is placed between the turbo and the intake manifold. Yes, the intercooler is in there too, but the important part is that the BPV is placed on the "charged" pipe, or the pipe with boost in it. The intake pipe that is between the MAF and the turbo is not "charged" as air in there hasn't been through the turbo yet.
When you VTA (Vent to Air) using a BOV (Blowoff Valve), a large amount of air that has been through the MAF (fuel already added for) gets dumped into the engine bay causing an immediate extreme rich condition every time the BOV vents. Rich causes poor running, stumbling, bad spool recovery, etc...
When you RECIRC (recirulate the air from the "charged" pipe to the intake pipe) using a BPV (Bypass Valve), the compressed air after the turbocharger is rerouted back BEFORE the turbocharger... but after the MAF... so no air is lost and the already added fuel can mix properly.
What causes the BOV/BPV to open? A vaccum line is connected to the unit which is plugged into the intake manifold. When the driver lifts-throttle or shifts, the throttle plate closes. Now the engine is trying to suck air past the throttle plate rather than allowing the turbocharger to force air past it. This is called "vaccum". But the turbocharger hasn't completely spooled down and is still trying to force boost past the closed throttle plate... so you want to let that air out. You want to let the air out because when that boosted air slams into a closed throttle plate, a huge amount of pressure is created... enough pressure to actually break the rotating assembly of the turbocharger (that's spinning at 100,000rpm). The vaccum in the intake manifold sucks the piston in the BPV open through the line connected to it. As soon as you open the throttle again and the vaccum is reduced, the spring in the BPV closes the valve again and seals the system... and boost actually holds the valve closed, so it shouldn't leak.
So, you vent that air... either into the engine bay, or back into the intake piping after the MAF.
Stock OEM BPV's are designed to hold a specific amount of boost and respond a specific way in vaccum-to-boost transitions for the specific characteristics of that engine in that vehicle. Replacing one that performs differently than stock (hold more boost, vent faster, leak in vaccum, leak under boost) will yield predictable results.
Recent research has shown that it's very unlikely the MS6 OEM BPV leaks under boost... and that it actually responds very fast during when it actuates. Some of the smarter people in the MS6/MS3 community say the OEM BPV is the best overall performing BPV when talking about how much the stock ECU likes it... but it doesn't have that super-cool penis enlarging sound.
A happy medium to get the cool sound and keep the OEM ECU happy is one of the dual-port valves that VTA's some air, and RECIRC's the rest.
Yes, it is perfectly fine to run a BPV with an otherwise completely stock engine... the Forge piece is a direct bolt-on, and when tuned right should work better than stock. Most people running a dual-port valve on an otherwise stock engine will say they have no problems. Some people running VTA on a stock engine will tell you it works fine, but won't let anybody else drive their car.
More air entering = more fuel needed.
In the MS6, air passes through the filter, then the MAF, then to the turbo, then to the intake manifold. The OEM BPV (as in any turbocharged car) is placed between the turbo and the intake manifold. Yes, the intercooler is in there too, but the important part is that the BPV is placed on the "charged" pipe, or the pipe with boost in it. The intake pipe that is between the MAF and the turbo is not "charged" as air in there hasn't been through the turbo yet.
When you VTA (Vent to Air) using a BOV (Blowoff Valve), a large amount of air that has been through the MAF (fuel already added for) gets dumped into the engine bay causing an immediate extreme rich condition every time the BOV vents. Rich causes poor running, stumbling, bad spool recovery, etc...
When you RECIRC (recirulate the air from the "charged" pipe to the intake pipe) using a BPV (Bypass Valve), the compressed air after the turbocharger is rerouted back BEFORE the turbocharger... but after the MAF... so no air is lost and the already added fuel can mix properly.
What causes the BOV/BPV to open? A vaccum line is connected to the unit which is plugged into the intake manifold. When the driver lifts-throttle or shifts, the throttle plate closes. Now the engine is trying to suck air past the throttle plate rather than allowing the turbocharger to force air past it. This is called "vaccum". But the turbocharger hasn't completely spooled down and is still trying to force boost past the closed throttle plate... so you want to let that air out. You want to let the air out because when that boosted air slams into a closed throttle plate, a huge amount of pressure is created... enough pressure to actually break the rotating assembly of the turbocharger (that's spinning at 100,000rpm). The vaccum in the intake manifold sucks the piston in the BPV open through the line connected to it. As soon as you open the throttle again and the vaccum is reduced, the spring in the BPV closes the valve again and seals the system... and boost actually holds the valve closed, so it shouldn't leak.
So, you vent that air... either into the engine bay, or back into the intake piping after the MAF.
Stock OEM BPV's are designed to hold a specific amount of boost and respond a specific way in vaccum-to-boost transitions for the specific characteristics of that engine in that vehicle. Replacing one that performs differently than stock (hold more boost, vent faster, leak in vaccum, leak under boost) will yield predictable results.
Recent research has shown that it's very unlikely the MS6 OEM BPV leaks under boost... and that it actually responds very fast during when it actuates. Some of the smarter people in the MS6/MS3 community say the OEM BPV is the best overall performing BPV when talking about how much the stock ECU likes it... but it doesn't have that super-cool penis enlarging sound.
A happy medium to get the cool sound and keep the OEM ECU happy is one of the dual-port valves that VTA's some air, and RECIRC's the rest.
Yes, it is perfectly fine to run a BPV with an otherwise completely stock engine... the Forge piece is a direct bolt-on, and when tuned right should work better than stock. Most people running a dual-port valve on an otherwise stock engine will say they have no problems. Some people running VTA on a stock engine will tell you it works fine, but won't let anybody else drive their car.
Last edited:
boost2dms6
Member
I think that your post SamNavy is very informative to people that know little about boosted cars and how they work.. Finally a educational post instead of an opinion..
lakedude90
Member
i would have to agree. i knew a lil about turbos and BOV/BPVs nut this is ver helpful. deff gonna keep all this in mind
- :
- 2007 Mazdaspeed 6 Sport
SamNavy,
Thanks for serving! (Former US Marine here)
While I agree with 99% of your post, I feel that you left out something important to note about the stock BPV. It should be noted that under high levels of boost (18psi or more) after prolonged use the plastic flange can very easily bend up off the seat allowing boosted air to escape. This plastic material is not ideal for high-heat applications either (it's just cheaper).
Thanks for serving! (Former US Marine here)
While I agree with 99% of your post, I feel that you left out something important to note about the stock BPV. It should be noted that under high levels of boost (18psi or more) after prolonged use the plastic flange can very easily bend up off the seat allowing boosted air to escape. This plastic material is not ideal for high-heat applications either (it's just cheaper).
nice first post samnavy! me, and my wife and baby appreciate those who serve and protect this county....thank you!!!!
i'd like to add that the turbosmart dual port- though awesome sounding it is-does leave you with some backfires. i've found it impossible to adjust it out. granted it only does it once or twice whenever i drive.
i recently put the stock valve back on, and been driving for a week now on it. and i must agree with some others that it does feel like it runs better. especially on/off part throttle stuff.
i notice using the cruise control to accelerate is smoother. and not jerky.
so i may just stick with the stock bpv. though i miss the fantastic whip crack of the dual port. might just post it up fs. real soon.
i'd like to add that the turbosmart dual port- though awesome sounding it is-does leave you with some backfires. i've found it impossible to adjust it out. granted it only does it once or twice whenever i drive.
i recently put the stock valve back on, and been driving for a week now on it. and i must agree with some others that it does feel like it runs better. especially on/off part throttle stuff.
i notice using the cruise control to accelerate is smoother. and not jerky.
so i may just stick with the stock bpv. though i miss the fantastic whip crack of the dual port. might just post it up fs. real soon.
boost2dms6
Member
Anybody have a review of the SU Turbosmart BPV? Not the dual port one but the full recirc. one..
- :
- 2011 Mustang GT
One of our local guys just picked up one from SU, I'm waiting to check it out soon.
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